Chicago invested heavily in Designated Players Nery Castillo and Freddie Ljungberg, but they're running out of time to make a playoff push. Winless in five straight, they're currently seven points back of the eighth and final playoff berth and need to make up ground fast.

This match is more important for the Fire than it is for Real Salt Lake, who have already surely secured a spot. However, w are talking Rio Tinto Stadium, andRSL take a lot of pride in defending their “fortress.” In fact, they will be looking to break their currently shared MLS-record home unbeaten streak on Saturday, and Chicago stand in the way of their 23rd consecutive unbeaten match at home.

Real Salt Lake

RSL's injury woes continue as defender Robbie Russell is likely to miss the match due to a concussion sustained in Wednesday's CONCACAF Champions League match against Toronto. Ned Grabavoy has joined the ranks of the healthy, although Salt Lake will be missing Javier Morales, who is suspended for this match.

On the forward front, Fabian Espindola may still be missing, and Robbie Findleyhas had trouble finishing in recent weeks. But RSL has good backup from the striker position in USSF D2 loanee Paulo Jr., who scored in his MLS debut against Toronto.

Chicago Fire

Coach Carlos de los Cobos says every game from here on out is do-or-die for the Fire, and he's right. The time is now for Chicago to pick up momentum, regardless of the daunting task at Rio Tinto.

"We must depend on no one but ourselves," de los Cobos wrote on chicago-fire.com. "If we have any hope of qualifying for the playoffs, we must stop erring where we’ve erred, be more focused and stay poised at all times."

The Mexican coach will receive some help in the midfield with the signing of Bratislav Ristic. The Serb, who has been training with the team for some time, may be available, pending the receipt of his International Transfer Certificate.

The back four for the Fire appeared ready to settle in following the return of Gonzolo Segares from suspension and with the recent emergence of Deris Umanzor at left back. However, reports out of Chicago indicate that both Steven Kinney and Dasan Robinson are struggling through injuries.

The good news is that it looks as if midfielder Marco Pappa is set for his return after an injury suffered whie the Guatemalan star was off with his national team.

Heroes & villains

Alvaro Saborio vs. Logan Pause: RSL's Costa Rican star has been playing what coach Jason Kreis has called “his best soccer of the season." The striker likes to come back to meet the ball, and is very effective at playing it off to the advancing midfielders. Pause will be the man tasked with fighting him off, and keeping him from roaming into open space. The Fire's holding mid has the discipline to do so, but will have his hands full with Saborío.

Stat that makes you go “Hmm"

Chicago have just two wins against Western Conference opponents in 11 tries this season. Meanwhile, Real Salt Lake have won all seven home encounters against Eastern Conference foes this year.